1. Field of the Invention
The present invention relates to an electronic camera having an electronic zoom function whereby a portion of an image obtained by capturing an image of a subject is displayed in an enlargement and an optical viewfinder.
2. Description of the Related Art
There are single or fixed focus type electronic still cameras in the prior art that have a function of enlarging the central portion of an image created at an image-capturing element through image processing to obtain an image that appears as if it were photographed with a telephoto lens. Hereafter, this function is referred to as "electronic zoom."
It is to be noted that the enlarged image obtained through the electronic zoom may be displayed on, for instance, a liquid crystal display provided at the camera body of the electronic still camera.
In addition, some electronic still cameras that are provided with a zoom lens to perform optical zooming (hereafter referred to as "optical zoom") are also capable of achieving electronic zoom.
With such an electronic still camera, even when the zoom-in achieved through the optical zoom has reached its limit, for instance, an image that appears as if it were photographed at a focal length that is longer than the actual focal length can be created by implementing a zoom-in through the electronic zoom.
FIGS. 5A and 5B illustrate the relationship between the zooming and the focal length achieved through the optical zoom and the electronic zoom. In the figures, the "actual focal length" indicates the focal length determined through the optical zoom, whereas the "synthesized focal length" represents the focal length determined by combining the optical zoom and the electronic zoom.
Normally, an electronic still camera capable of optical zoom is provided with an optical zoom viewfinder at which the range of the subject within the viewfinder screen can be varied by moving the viewfinder lens.
However, since the range of the subject is changed in conformance to the actual focal length at the optical zoom viewfinder, the range of the subject within the viewfinder screen cannot be changed if the zoom-in achieved through the optical zoom has reached its limit, as illustrated in FIG. 5A.
In addition, as illustrated in FIG. 5B, if a zoom-in is implemented through the electronic zoom while a zoom-in through the optical zoom is in progress, it is difficult to move the viewfinder lens in conformance to the electronic zoom and, as a result, it is not possible to match the range of the subject within the viewfinder screen with the range of the subject displayed on a liquid crystal display or the like.
Thus, there is a concern that when the photographer performs photographing while monitoring the optical viewfinder, he may not realize that the electronic zoom is set and he may press the release button thinking erroneously that the image of the subject as seen in the viewfinder will be recorded.
In other words, there is a problem in that, in such a case, since the range of the subject, whose image is photographed while the electronic zoom is set, does not match the range of the subject within the viewfinder screen, an image that the photographer does not expect is recorded.
It is to be noted that electronic still cameras having an optical viewfinder (including an optical viewfinder without a zooming function) among the single focus type electronic still cameras described earlier, too, have a similar problem.